LEV Testing

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Local Exhaust Ventilation (LEV) systems play a crucial role in protecting workers from hazardous airborne contaminants in industrial environments. However, their effectiveness relies on proper design, regular maintenance, and thorough testing. LEV testing is not just a regulatory requirement under COSHH (Control of Substances Hazardous to Health) in the UK—it’s a critical safety measure.

Here are 10 essential do’s and don’ts to guide your LEV testing program and ensure your systems operate efficiently and compliantly.

Regular testing (at least every 14 months, or more frequently for certain processes) is essential to maintain compliance and ensure ongoing system effectiveness.

❌ Don’t Wait for Something to Go Wrong
Ignoring small performance dips can lead to exposure risks or full system failures. Don’t be reactive—be proactive.

Ensure LEV tests are conducted by competent persons trained in air movement, LEV design, and measurement techniques (e.g. BOHS P601 certified).

❌ Don’t DIY If You’re Not Qualified
Untrained personnel may miss critical issues or misinterpret results, rendering the test ineffective and non-compliant.

Check for blockages, damage, and wear in hoods, ducting, filters, and fans. Airflow readings alone don’t tell the full story.

❌ Don’t Rely on Numbers Alone
Good airflow doesn’t always mean good capture efficiency. Physical deterioration or poor positioning can make even a system with “good” airflow ineffective.

Use the original design performance benchmarks or HSE standards to assess if the system is performing as intended.

❌ Don’t Test in Isolation
Testing without comparing to the original design data is like checking your speed without knowing the speed limit—it lacks context.

Each LEV system should have a unique ID, a test record, and a visible label with the date of the last and next test.

❌ Don’t Let Records Get Lost
Inadequate documentation can land you in legal trouble and hinder future troubleshooting or upgrades.

Use calibrated devices for measuring airflow, pressure, and capture velocity. Confirm tools are within their calibration date.

❌ Don’t Use Faulty or Outdated Equipment
Old, uncalibrated tools give unreliable readings, making your entire test invalid.

Operators know the day-to-day challenges of working with LEV. Include them in feedback loops and educate them about proper use.

❌ Don’t Ignore Misuse or Misunderstanding
Poor usage (e.g. working outside the capture zone) can nullify even the best-designed systems.

Evaluate how the system performs during actual working conditions—not just when the equipment is idle.

❌ Don’t Test Only Under Ideal Conditions
LEV needs to protect workers during real operations, which often introduce turbulence, heat, or unexpected variables.

Any system that fails testing should be repaired, retested, and recorded promptly.

❌ Don’t Delay Repairs
Allowing faulty systems to run exposes workers and violates HSE regulations.

COSHH and HSE guidance evolve. Ensure your testing practices align with the latest standards, such as HSG258.

❌ Don’t Assume What Was OK Last Year Still Applies
Standards and best practices can change. Stay informed to stay compliant.

LEV testing is a vital component of workplace health and safety. Treat it not just as a legal obligation, but as an opportunity to protect your workforce, extend equipment life, and improve operational efficiency.

By following these do’s and don’ts, you’ll ensure your LEV systems are doing their job—and doing it well.

Local Exhaust Ventilation (LEV) systems are designed to capture and remove hazardous airborne contaminants in the workplace—like dust, fumes, vapors, and gases—before they can be inhaled by employees. To ensure these systems are functioning effectively, regular LEV testing is essential.

Here’s how the LEV testing process is typically carried out:

The process begins with a thorough visual check of the entire LEV system. This includes:

• Hoods and capture devices
   
• Ductwork for wear or blockages
   
• Filters, fans, and discharge points
   
• General condition and cleanliness of the system
   

Each LEV system is identified and cross-referenced with existing documentation, such as:

• Technical drawings
   
• Control strategies
   
• Previous test reports
   
• Manufacturer's specifications
   

Specialist instruments are used to assess:

• Face velocity at the hood opening
   
• Capture velocity near contaminant sources
   
• Static and dynamic pressure at key points
   

These measurements help determine if the airflow is within the designed range and effective in capturing contaminants.

Testers assess whether the LEV system is:

• Controlling contaminants at source
   
• Compliant with COSHH Regulation 9 requirements
   
• Consistent with its original design performance
   

Smoke tests or dust lamp tests may be used for visual confirmation of airflow paths.

All testing equipment must be calibrated and traceable to national standards to ensure accuracy and reliability of results.

A detailed report is issued that includes:

• System diagrams and performance data
   
• Observations on wear or inefficiency
   
• Recommendations for repair, maintenance, or improvement
   
• A clear pass/fail assessment
   

Each system should also be labeled with the test date and the next due test date.

LEV testing isn’t just a regulatory box-tick—it’s a crucial part of protecting health and safety in the workplace. Whether you're in manufacturing, welding, woodworking, or lab environments, make sure your LEV systems are tested by competent professionals at least every 14 months.